[ELF] Ignore R_*_NONE relocs when relocating non-alloc sections

We shouldn't report an error for R_*_NONE relocs since we're emitting
them when writing relocations to discarded sections.

Differential Revision: https://reviews.llvm.org/D30279

llvm-svn: 295936

6 files changed, 31 insertions, 7 deletions

diff --git a/lld/ELF/InputSection.cpp b/lld/ELF/InputSection.cpp
index 66405f1d2a5..4fae7dd0d3b 100644
--- a/lld/ELF/InputSection.cpp
+++ b/lld/ELF/InputSection.cpp
@@ -308,6 +308,7 @@ getRelocTargetVA(uint32_t Type, int64_t A, typename ELFT::uint P,
                  const SymbolBody &Body, RelExpr Expr) {
   switch (Expr) {
   case R_HINT:
+  case R_NONE:
   case R_TLSDESC_CALL:
     llvm_unreachable("cannot relocate hint relocs");
   case R_TLSLD:
@@ -459,7 +460,10 @@ void InputSection<ELFT>::relocateNonAlloc(uint8_t *Buf, ArrayRef<RelTy> Rels) {
       Addend += Target->getImplicitAddend(BufLoc, Type);
 
     SymbolBody &Sym = this->getFile<ELFT>()->getRelocTargetSym(Rel);
-    if (Target->getRelExpr(Type, Sym) != R_ABS) {
+    RelExpr Expr = Target->getRelExpr(Type, Sym);
+    if (Expr == R_NONE)
+      continue;
+    if (Expr != R_ABS) {
       error(this->getLocation<ELFT>(Offset) + ": has non-ABS reloc");
       return;
     }
diff --git a/lld/ELF/Relocations.cpp b/lld/ELF/Relocations.cpp
index 731023dc244..871b1b0d37f 100644
--- a/lld/ELF/Relocations.cpp
+++ b/lld/ELF/Relocations.cpp
@@ -694,6 +694,11 @@ static void scanRelocs(InputSectionBase &C, ArrayRef<RelTy> Rels) {
       reportUndefined<ELFT>(Body, C, RI.r_offset);
 
     RelExpr Expr = Target->getRelExpr(Type, Body);
+
+    // Ignore "hint" relocations because they are only markers for relaxation.
+    if (isRelExprOneOf<R_HINT, R_NONE>(Expr))
+      continue;
+
     bool Preemptible = isPreemptible(Body, Type);
     Expr = adjustExpr(*File, Body, IsWrite, Expr, Type, Buf + RI.r_offset, C,
                       RI.r_offset);
@@ -732,9 +737,7 @@ static void scanRelocs(InputSectionBase &C, ArrayRef<RelTy> Rels) {
       continue;
     }
 
-    // Ignore "hint" and TLS Descriptor call relocation because they are
-    // only markers for relaxation.
-    if (isRelExprOneOf<R_HINT, R_TLSDESC_CALL>(Expr))
+    if (Expr == R_TLSDESC_CALL)
       continue;
 
     if (needsPlt(Expr) ||
diff --git a/lld/ELF/Relocations.h b/lld/ELF/Relocations.h
index 1512a674480..f531b99f1b9 100644
--- a/lld/ELF/Relocations.h
+++ b/lld/ELF/Relocations.h
@@ -42,6 +42,7 @@ enum RelExpr {
   R_MIPS_TLSGD,
   R_MIPS_TLSLD,
   R_NEG_TLS,
+  R_NONE,
   R_PAGE_PC,
   R_PC,
   R_PLT,
diff --git a/lld/ELF/Target.cpp b/lld/ELF/Target.cpp
index 08ef75d1665..a05ff79a6d9 100644
--- a/lld/ELF/Target.cpp
+++ b/lld/ELF/Target.cpp
@@ -389,7 +389,7 @@ RelExpr X86TargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S) const {
   case R_386_TLS_LE_32:
     return R_NEG_TLS;
   case R_386_NONE:
-    return R_HINT;
+    return R_NONE;
   default:
     error(toString(S.File) + ": unknown relocation type: " + toString(Type));
     return R_HINT;
@@ -684,7 +684,7 @@ RelExpr X86_64TargetInfo<ELFT>::getRelExpr(uint32_t Type,
   case R_X86_64_GOTTPOFF:
     return R_GOT_PC;
   case R_X86_64_NONE:
-    return R_HINT;
+    return R_NONE;
   default:
     error(toString(S.File) + ": unknown relocation type: " + toString(Type));
     return R_HINT;
@@ -1715,7 +1715,7 @@ RelExpr ARMTargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S) const {
   case R_ARM_THM_MOVT_PREL:
     return R_PC;
   case R_ARM_NONE:
-    return R_HINT;
+    return R_NONE;
   case R_ARM_TLS_LE32:
     return R_TLS;
   }
diff --git a/lld/test/ELF/Inputs/relocatable-non-alloc.s b/lld/test/ELF/Inputs/relocatable-non-alloc.s
new file mode 100644
index 00000000000..26a9d87db75
--- /dev/null
+++ b/lld/test/ELF/Inputs/relocatable-non-alloc.s
@@ -0,0 +1,6 @@
+.section .text.foo,"axG",@progbits,foo,comdat,unique,0
+foo:
+  nop
+
+.section .debug_info
+.long .text.foo
diff --git a/lld/test/ELF/relocatable-non-alloc.s b/lld/test/ELF/relocatable-non-alloc.s
new file mode 100644
index 00000000000..f1915800c77
--- /dev/null
+++ b/lld/test/ELF/relocatable-non-alloc.s
@@ -0,0 +1,10 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t1.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %S/Inputs/relocatable-non-alloc.s -o %t2.o
+# RUN: ld.lld %t2.o %t2.o -r -o %t3.o
+# RUN: ld.lld %t1.o %t3.o -o %t.o | FileCheck -allow-empty %s
+
+# CHECK-NOT:  has non-ABS reloc
+
+.globl _start
+_start: